The present application relates to a thermal insulating or fire retardant construction element and a lead-through duct for leading smoke pipes therethrough, in accordance with the preamble in claims 1 and 8 below.
To date, it has been usual to construct thermal insulating or fire retardant walls, for example, in connection with fireplaces, with construction blocks of solid, isotropic material, such as, e.g., Leca (light expanded clay aggregate) or Siporex. This is a very labour-intensive operation, as the construction blocks must first be laid one by one and then the wall must be plastered. This takes a long time and causes a lot of dust and dirt in the vicinity the work place. Moreover, the weight of a wall of this kind is great, about 90 kg/m.sup.2 wall.
Construction elements comprising layers of insulating material are known in general from, e.g., SE 415 845 and GB-1 252 562. However, these are designed for the outer walls of a construction and are not constructed for and will not be suited to insulation between a fireplace and a combustible wall.